Heat control device for ovens and the like



Jan. 3, 1933. c. w. ROBERTSHAW HEAT CONTROL DEVICE FOR OVENS AND THE LIKE Filed Sept. 19, 1928 3 Sheets-Sheet Q J 1 M :u I 3 8 q. 12 flu; i r J g f u 2 A Q i A m H L T @O O C, A mm 4 /@MW 5 f F r a L L INVENTOR C. W. RQBERTSHAW HEAT CONTROL DEVICE FOR OVENS AND THE LIKE Filed Sept. 19, 1928 L5 Sheets-Sheet s. W. ROBERTSHAW 1i,892 89 I HEAT CONTROL DEVICE FOR OVENS AND THE LIKE Filed Sept. 19, 1928 5 Sheets-=$heet 5 INVENTOR Patented Jan. 3%, i123 CLARENCE W. ROBERTSHAW, OF YOUNG-WOOD, PENNSYLVANIA, ASSIGNOB T ROBERT- SHAW' THERMOS TAT COMPANY, OF YOUNGWOOD, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA HEAT CONTROL DEVICE FOR OVENS AND THE LIKE Application filed September 19, 1928. Serial No. 306,835.

This invention relates generally to heat control devices and more particularly to a device for regulating the temperatures in gas ranges, ovens and the like.

It has heretofore been proposed in the art to which this invention relates to provide an oven with a clock mechanism adapted to control the flow of gas to the burner of the oven. In these prior devices it has been customary to pass all of the gas which flows to the main burner through the clock mechanism. This practice has the disadvantage that in order to control the flow of the main supply of gas through a clock mechanism it has been necessary to provide the clock mechanism with relatively large valves which are not easily operated and which tend to fail in operation due to the tendency of the valve to stick because of the friction developed within the valve.

4 In accordance with my invention a relatively small portion only of the gas used in the main burner is passed through and controlled by the clock mechanism. My device provides an arrangement in which a relatively small valve may be used in connection with the clock mechanism thereby eliminating or decreasing the tendency of the valve to stick.

My device includes a main gas valve for: controlling the supply of gas to the main gzut burner. The main gas valve is in turn controlled by a thermostatic element which is controlled by a portion only of the gas supply.

Referring to the accompanying drawings which illustrate the present preferred embodiment of my invention Figure 1 is a front elevation of a gas range and heat control de vice. Fig. 2 is a plan view and Fig. 3 is an end elevation. 1

p I Referring to the drawings the gas range is provided with a main gas conduit, 2 which is connected to a source of gas supply. A branch 3 of the conduit 2 leadstothe individual burners controlled, by the valves 4. This part of the device may be of any desired construction and forms no part of the present invention. A gas supply pipe 5 connects the conduit 2 to: a valve 6, which controls the flow of gas to the main burner 7 arranged within the oven, 8. The conduit 5 is provided with a shut-off valve 10 by means of p which the supply of gas to the gas range may mechanism is connected. The pipe 11 is pro vided with a valve 11' by means of which the amount of gas flowing through the pipe 11 may be controlled. A second small pipe 12 is adapted to conduct the gas flowing into the clock A through the pipe 11, from the clock mechanism and deliver it to an auxiliary, burner 13 arranged within the oven. A thermostatic element 14 isarranged adjacent the auxiliary burner 13 and is operably connected with the valve 6 which controls the flow of gas from the conduit 5 to the main burner 7. A pipe 16 connects a pilot burner 17 with the conduit 5.

A second thermostatic element 18 is arranged adjacent the top of the oven 8 and is operably connected to a thermostatic valve 19 adapted to control. the temperature within the oven. This thermostatic element 18 and the valve .19 operated thereby may be of any usual or deslred construction.

In the operation of the device, assuming the oven to be cold, the gas flows through conduits 2 and 5 to the valve, 6. The valve 6 is at this time closed so that the main suply of gas cannot flow by it to th'emain urner "7. A portion only of the gassupply does however fiowthrough pipe 11 to the clock mechanism A and if the valve operated by the clock mechanism is open the gas entering the clock mechanism through the pipe 11 flows through the pipe 12 tothe auxiliary burner 13.- Assuming that the pilot burner is lighted, the gas flowing from the auxiliary burner 13 =willbe lighted. This results in a flame "13' which impinges directly on the,thermostaticelement 14 and heats it. The main valve 6 is of such a construction that it opens when the thermostatic element 14 is heated. The main valve 6 therefore opens and allows the main supply of gas from the conduit 5 to flow through the valve 6 to the main burner 7. The-main valve 6 Will remain open as long as gas is supplied to the auxiliary burner 13 thereby providing a flame 13 which heats the thermostatic element 1 1 and maintains the valve 6 open. WVhen the clock valve closes in accordance with the time for which the clock has been set, the gas supply to the auxiliary burner 13 is cut oil. The thermostatic element 14 therefore cools and the main valve 6 closes.

The desired temperature within the oven is controlled by the thermostatic element 18 and the thermostatic valve 19 controlled thereby.

My device provides a very effective and safe means for time and temperature control. The main supply of gas does not pass through the clock operated valve but instead only a relatively small proportion of the gas supply to the main burner is passed through the clock mechanism. The amount of gas passing through the clock mechanism is only about twocubic feet per hour. In case the person operating the gas range were to attempt to operate the range when the pilot burner was not lighted, the only gas which would flow into the oven Would be the small proportion flowing through the clock mechanism. As the average time of cooking a meal would not normally exceed three hours the total amount of gas flowing into the gas oven from the clock mechanism would not exceed six cubic feet. This amount is not enough to cause an explosion. My device therefore provides a system in which even though the pilot burner is not lighted when the clock mechanism is set, suflicient gas to cause an explosion cannot be delivered to the gas oven.

In my device the valve 6 controlling the main supply of gas to the oven is controlled by the thermostatic element 14 and the thermostatic element is in turn controlled by the direct impingement of the flame 13' against the element. This enables me to employ a main valve 6 which opens 'at a very high temperature. This means that the main gas valve will therefore close at a comparatively high temperature and that it will close rapidly as soon as the gas supply to the auxiliary burner 13 is cut off, even though the temperature of the oven is high.

I have illustrated and described the present preferred embodiment of my invention. It is to be understood however that the invention may be otherwise embodied without departing from the spirit of the invention or the scope of the following claims,

I claim:

1. An oven provided with a burner, a conduit for supplying gas to the burner, a main valve in said conduit, auxiliary conduits leading from the main conduit and adapted to convey a portion only of the gas in the main conduit, a clock mechanism for controlling the flow of gas in the auxiliary conduits, and means dependent upon flow of gas in said auxiliary conduits for operating said main valve, said means including a thermostatic element.

2. An oven provided with a burner, a conduit for supplying gas to the burner, a main valve in said conduit, auxiliary conduits lead-' ing from the main conduit and adapted to convey a portion only of the gas in the main conduit, a clock mechanism for controlling the flow of gas in the auxiliary conduits, an auxiliary burner controlled by said clock mechanism, a pilot light, and means controlled by said auxiliary burner for operating the main valve.

3. An oven provided with a burner, a conduit for supplying gas to the burner, a main valve in said conduit, auxiliary conduits leading from the main conduit and adapted to convey a portion only of the gas in the main conduit, a clock mechanism for controlling the flow of gas in the auxiliary conduits, an auxiliary burner controlled by said clock mechanism, a pilot light, and a thermostatic element controlled by said auxiliary burner for operating the main valve.

1. An oven provided with a burner, a conduit for supplying gas to the burner, a main valve in said conduit, auxiliary conduits leading from the main conduit and adapted to convey a portion only of the gas in the main conduit, a clock mechanism for controlling the flow of gas in the auxiliary conduits, an auxiliary burner controlled by said clock mechanism and giving an unvarying flame while gas flows through saidclock mechanism, a pilot light, and a thermostatic element controlled by said auxiliary burner for operating said main valve.

5. An oven provided with a burner, a conduit for supplying gas to the burner, a main valve in said conduit, auxiliary conduits leading from the main conduit and adapted to convey a portion only of the gas in the main conduit, a clock mechanism for controlling the flow of gas in the auxiliary conduits, an auxiliary burner controlled by said clock mechanism, a pilot light, and a thermostatic element arranged to be heated directly by the flame of said auxiliary burner for operating said main valve.

6. An oven provided with a burner, 11 conduit for supplying gas to the burner, a main valve in said conduit, auxiliary conduits leading from the main conduit and adapted to convey a portion only of the gas in the main conduit, a clock mechanism for controlling the flow of gas in the auxilia conduits, an auxiliary burner controlled y said clock mechanism, a pilot light, and a thermostatic element controlled by said auxiliary burner for operating'said main valve, said pilot light being arranged to light said auxiliary burner. In testimony whereof I have hereunto set my hand.

CLARENCE W. ROBERTSHAW. 

